How to Use the Password Strength Checker
Type or paste your password into the input field above to instantly check your password strength. Our password strength checker analyzes your input across dozens of security criteria — length, character variety, entropy, common patterns, breach databases, and more. No data ever leaves your browser, making it one of the most private password security tools available online.
What Is Password Entropy and Why Does It Matter?
Password entropy measures how unpredictable — and therefore how secure — a password is against brute-force attacks. It is calculated as: Entropy = Length × log₂(CharacterPool). A password with 80+ bits of entropy is considered very strong. Adding just a few more characters or introducing a new character type (uppercase, symbol, number) dramatically increases entropy and password security. Our password strength test shows your exact entropy score in bits.
What Makes a Strong Password?
A strong password combines length (16+ characters), variety (uppercase, lowercase, numbers, symbols), randomness (no dictionary words or patterns), and uniqueness (never reused across sites). Our password security checker evaluates all of these dimensions and gives you actionable suggestions to improve your password strength score instantly.